输入N组父子对，求父子对所组成的二叉树的高度----17年某公司的笔试题

import java.util.Scanner;

public class Main {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        Scanner scanner = new Scanner(System.in);
        while(scanner.hasNext()){
            int groups = scanner.nextInt();
            int[][] matrix = new int[groups][2];for(int i=0;i<groups;i++){
                for(int j=0;j<2;j++){
                    matrix[i][j] = scanner.nextInt();
                }
            }
　　　　　　　　//动态规划输出处理
              System.out.println(maxHightHelper(matrix));

        }
    }//动态规划
    public static int maxHightHelper(int[][] matrix){
        if(matrix==null||matrix.length==0)
            return 0;    
        //记录当前组的高度
        int[] hight = new int[matrix.length];
        for(int i=0;i<hight.length;i++)
            hight[i] = 1;
         byte[] visited = new byte[matrix.length];
        for(int i=0;i<matrix.length;i++){
            if(visited[i]==0){
                visited[i] = 1;
                hight[i] = hight[i]+1;
            }
            for(int j=i+1;j<matrix.length;j++){
                if(matrix[j][0]==matrix[i][1]&&visited[j]==0){
                    visited[j] = 1;
                    hight[j] = hight[i] +1;
                }
            }
        }
        //找最大的高度
        int max = 0;
        for(int i=0;i<hight.length;i++){
            if(max<hight[i])
                max = hight[i];
        }
        return max;
    }
}